Brian's Research
Board-to-Board Optical Interconnect: Lens Alignment System Incorporating Ultrasonic Stepper Motors
Introduction
An array of free-space optical interconnects composed of vertical cavity
surface emitting lasers (VCSELs), alignment lenses, and photodiodes can
alleviate communication limitation between boards in computer servers by
replacing traditional copper wire connections. Actively controlled
alignment lenses can be used to correct optical misalignment due to
vibration loads, temperature fluctuation, and initial static offsets. A
silicon micro-machined lens stage has been designed to interface between
piezoelectric based ultrasonic stepper motors (USM) and a bulk alignment
lens for the VCSEL array. The stepper motors offer a distinct advantage
of zero power requirement once the lens is aligned, with position
maintained by the internal friction force of the motor. The linear USMs
have been characterized under a no-load configuration and provide 1 micron
position resolution with more than a millimeter of travel range.